1. Field of the Invention
The invention relates to a filter cartridge for liquid media at risk for freezing, in particular, for use in fuel cell operated vehicles and in internal combustion engines, preferably diesel engines. The filter cartridge comprises a housing that is closable by a filter lid. A filter insert is arranged in the housing and has at least one filter element which is positioned between terminal parts and is axially tensioned by at least one tensioning part.
2. Description of the Related Art
In known filter cartridges of this type, the filter element is arranged between two end plates of the filter insert. They are axially pretensioned by means of a pretensioning ring, respectively, relative to the filter element when the filter insert is inserted into the filter housing. Because of the contact of the pretensioning rings on the housing, between the upper and lower end plates a torque is produced so that the end plates are twisted relative to one another. Accordingly, the filter elements of the filter insert position themselves in a slanted position so that they become shorter. This results in a decrease of the axial pretension. When medium flows through the filter unit, the filter element is moreover widened so that it can no longer provide the axial pretensioning forces which are required for proper sealing. When the filter element becomes warped, the length of the filter cartridge is shortened which, in turn, results also in a decrease of the axial pretensioning forces. The filter element therefore can no longer properly ensure a reinforcement action for the filter cartridge.